Modification of rosin



Patented Sept. 4, 1945 MODIFICATION OF ROSIN Laszlo Auer, South Orange,N. J. v

No Drawing. Application October 12, 1942,

' Serial No. 461,794

Claims.

Grimsar. Finn or Invmrron AND Srarrmr or Osarcrs This invention relatesto treatment of rosin, and especially to treatment with certainmodifying agents promoting decarboxylation and/or other changes incharacteristics and properties. This application is acontinuation-in-part of my copending application SerialNo. 318,650,filed February 12, 1940 (now Patent 2,298,270).

As is known, gum or wood rosins contain mixtures of rosin acids, knowntoday as abietic acid,

pyro-abietic acid and d-pimaric acid amongst' others. Such rosinscommonly have an acid value of from about 145 to 185, usually from about180 to about 168, and in their natural state they are ordinarily hard,brittle materials, of melting point from about 70 C. to about 85 C.

Rosin is a valuable raw material for a number of commercial purposes,such as in paper sizing, soap manufacture, and especially in thecoatings and plastics industries. 'Ihere are, in fact, a

number of examples in the art of use of various rosin derivatives forpurposes such as'those mentioned. 'Some of the most important and commonexamples occur in the coatings industry, 1. e.,

use of rosin derivatives in paints, varnishes and ance with the presentinvention make it possible and advantageous to use the modified rosinproducts for many purposes for which rosin in its natural state and alsovarious derivatives thereof are not well suited.

To illustrate, reference is made to coating compositions, such asvarnishes. When employing the modified rosin products produced inaccordance with the present invention, the cooking of varnishes (usuallycontaining fatty oil plus resin) is accelerated, and in additionvarnishes cooked with modified rosinproducts produced by the presentmethod have improved drying properties. The modified rosin products maybe employed as apart of the film forming ingredients in coatingmaterials.

For certain special purposes inthe soap and paper sizing industries, themodified rosin products of this invention may also be of advantage,

notwithstanding the fact that the modified products may have a reducedacid value.

One of the important modifications which may be brought about by. theprocess of the invention is the decarboxylation of the rosin. Anotherimportant change which may be brought about is increased aggregation orpolymerization, various'of the modifications being discussed more fullyhereinafter.

In referring to changes of this type and in making comparisons of themodified products with products not treated with modifying agents, it isto be understood that the statements regarding changes and comparisonsare always made on the basis of a relation between the product treatedwith a modifying agent and a product treated in exactly the same manner(heating, etc.) .but without a modifying agent. The latter is oftenherein referred to as a blank or con-- trol experiment.

According to the invention, by appropriate control of treatmentconditions, and by appropriate selection of materials, the degree ofdecarboxylation and/or of other changes in properties includingaggregation may be regulated to meet various different requirements.

Tm: Momrrcarron Pnocsss The process of the invention involves heatingthe rosin in the presence of a modifying agent of the typementioned'hereinafter, the duration of heating, temperature and othertreatment conditions, as more fully explained herebelow, beingcontrolled in accordance with the extent and type of modificationdesired.

In general, modifying agents employed in accordance with this invention,and also in accordance with certain of my copending applications,identified hereinafter, are polar compounds. The present application isparticularly directed to the use of certain organic compounds asmodifying agents for rosin, especially substituted organic compoundshaving a residue of an oxygen-containing acid of nitrogen, such asnitroor nitrosocompounds.

Modifying agents of the type mentioned just above may be termedtwo-radical type compounds, by which I mean compounds having within themolecule an acidic inorganic nitrogenous residue, and ,an organicresidue, the inorganic residue being capable upon the addition ofhydrogen or OH groups, of yielding an inorganic nitrogencontaining acid.

With reference to the yielding of a nitrogencontaining acid, it may bementioned that e1 though I believe that the reaction takes place duringthe treatment ofthe rosin, in some cases the reaction may not occur toany considerable extent. Nevertheless, the treating agentshereincontemplated are effective, so'long as they have the capability ofyielding the corresponding nitrogen-containing acid, upon the additionof hydrogen or OH groups to the compound.

In fuller explanation of the capability of yielding thenitrogen-containing acid, it is to be understood that the acid may beproduced in different ways with different compounds. Thus, in someinstances, the addition of OH groups is required, derived, for example,from H2O. With some compounds the hydrogen or OH groups may be derivedfrom other parts of the molecule of the" treating agent itself (as bysplitting ofl under application of heat), and with others one or theother, or both, of the hydrogen and oxygen may be derived from anexternal source, such as the treatment atmosphere or some materialspresent in the reaction. In any event, all of the materialsin questionhave in common the capability of yielding a nitrogen-containing acid.

Modifying agents of the foregoing class are quite effective forpromoting aggregation or polymerization, and sometimes also in reducingthe acid value of rosin.

, Agents falling in the-above group may be of a number of dlflerenttypes, the following being representative:

Certain esters of inorganic acids have the important properties hereincontemplated, for instance-- Nitrocresol carbonate Again, some salts oforganic bases function in accordance with the invention. For example-,

n-Nitroaniline hydrochloride From the foregoing, it will be seen thatcertain treating agents in the class herein claimed may be relativelycomplex compounds incorporat ing, in addition to the nitrogen-containingresidue, other residues such, for instance, as a haloen-containingresidue capable of yielding a halogen-containing acid upon addition ofhydrogen In such cases the treating agent not only partakes of thedistinctive characteristics of the nitrogen-containing acid, but also ofcharacterlstics of the halogen-containing acids.

In this connection,- it is pointed out that in my copending applicationSerial No. 461,793, filed concurrently herewith, I have disclosed andclaimed other two radical type modifying agents having within -themolecule a halogen-containing residue.

In carrying out the process, the rosin is heated between about 100 C.and about 350 C., de-

pending upon the agent selected and the degree asegoer and natureofmodification desired. An advantageous temperature range with most ofthe:

particularly advantageous range with most agents to be from about 2% toabout 10%, although many of them are also effective in a lower range,such as from .5% to 5%.

Thorough dispersion of the modifying agent in the rosin is of importanceand appropriate control of temperature and time both contribute tobringing about such thorough dispersion. Agitation may be employed as anaid to securing thorough dispersion.

Usually not more than a few hours treatment on temperature will be foundsuillcient, for instance, from about one hour to above five hours,although in some cases the reaction proceeds very rapidly, requiring notmore than about one half hour.

The process may be carried out under varying conditions of pressure andgas air or other gas) and with variations of these conditions theproperties of the product will be varied, the effects of some of thesevariations being discussed shortly below. Thus the process may, forinstance, be

carried out at atmospheric pressure and in the presence of air, or maybe carried out in the absence of air, with pressure higher or lower orthe same as atmospheric pressure.

When it is desired to exclude air the reaction may be carried out in aclosed vessel, though not necessarily at a positive pressure, so thatthe gases or fumes of the reaction released from the modifying agent orfrom the reaction mass serve to exclude the air.

Vacuum is also effective for the purpose of excluding'air, and inaddition, reduction in contact of air may be brought about by blanketingthe surface of the reaction mixture with some inert gas, such as $02,CO2, or nitrogen. Where vacuum is used, a pressure, for instance, ofabout ms. Hg to about 450 mans. Hg will-be found and dispersion mediumare frequently altered;

Quite commonly, when employing modifying agents in accordance with thepresent application. the melting'point of the modified product is raisedas compared with a corresponding blank experiment. Although someinvestigators may consider this phenomenon as polymerization, I believethat at least certain changes which take place are of the character ofaggregation.

In any event, both polymerization and aggregation are usuallyaccompanied by a decrease in iodinevalue, and in the event ofpolymerization. the decrease in iodine value would be explained bychemical change, while in the event of ag regation it would beexplained, at least in part, by absorption phenomena.

Therefore, if the change "in physical characteristics and in iodinevalue is considered as caused by polymerization, there should be a cor-I believe, therefore, that aggregation is prob- 1 ably involved in thereaction. However, as will be seen from examples'given below, theaggregation is not necessarily followed by a corresponding increase inmelting point, at least to the extent which might be expected. This isis apparently explained by the fact that other changes and reactionstake place, including decarboxylation, to a greater or lesser degree,depending upon the particular modifying agent selected and also uponother treatment conditions, notably the pressure, temperature andatmospheric condition at the surface of the batch. Decarboxylation isnormally accompanied by decrease in acid value, and this effect usuallytends to decrease the melting point of the modified product.

In instances where the reaction is carried out below about 250 C., theextent of decarboxylation is commonly lower than where the temperatureis somewhat higher.

In general, it appears that the normal tendency of aggregation to raisethe melting point, is at least in part counteracted by the softening orliquefying action accompanying decarboxylation,

so that the end result is represented by the differential eii'ect ofthese two changes (and possibly also of other reactions).

In case of aggregation, change in the size and form of the miscellesprobably occurs.

In considering the nature of the modifications, 40

it is to be noted that, while some small loss in weight may occur byvolatilization (usually not more than about 15-20%), no appreciablefractional or destructive distillation takes place. With appropriateprecautions to avoid distillation the process can usually be carried outwithout loss of more than 5% or 10%, such small loss as does occurusually comprising water, 002, etc., at least in major part. As aprecaution, the temperature should be kept below the boiling ordistillation point of the main reaction product, under the appliedreaction conditions of the process. Bythis precaution, destructivedistillation or cracking is positively avoided.

The modified rosin product is quite unique, since the rosin moleculeretains almost as many carbon atoms as are present in the initial basicconstituents of the rosin, the number of carbon atoms being reduced onlyby that number involved in the decarboxylation.

It is or importance in securing various oi the foregoing characteristicsthat the reaction take place without any appreciable concurrentdistillation. In addition, the absence oi air and/or control oftemperature are important in avoiding destructive distillation.

Whatever the exact nature of the chemical, colloidal and/or physicalchanges which are brought about, the treatment provided in accordancewith the present invention makes possible the changing of the acid valueof the modified product, the

degreeof aggregation, and also the physical consistency of the material,the melting point sometimes being raised and sometimes lowered, ascompared with a corresponding blank" experiment. These changes, togetherwith others which usually take place, such as improving film formingproperties of the modified products; make possible or practicable use ofmy modified rosin products for many purposes for which rosin initsnatural state is not suited, or at least not well adaptable, and forwhich many known rosin derivatives are likewise not satisfactory.

By appropriate selection of modifying agent and treatment conditions,such as temperature, time, vacuum, etc I am enabled to control variousphysical properties of the modified products.

Exsurrss In a table given nerebelow, there are reproduced the results ofsome comparative experiments which were conducted under similar conditions, except for certain designated changes which serve to illustratedifferences in properties which may be secured by variations in process.

In all cases the experiments of this comparative series employed 5% ofthe organic mitts-coinpound and in all cases the treatment was conducted on W wood rosin (Newport industries), 1,000 gms. of the rosinbeing heated in a three liter distilling flask. The treatment period,was 5 hours. The treatment temperature was maintained fairly close tothe figures indicated in the table throughout the 5 hour treatmentperiod (usually within 10 C. plus or minus).

All temperatures are given in degrees centigrade.

Table of comparative experiments es. Acid Iodine Melting Agent T mm. Hgvalue value point 1 o-Nitrophenol 25') 400 112. l 138. 7 61 3 .-.d0. 290760 115.9 134.0 56- 3.- p-Nitrophenol 290 400 98. 2 l'Mnl 69. 8 4.. .do290 760 106.2 131.1 78.5 p onane. 290 400 m. 1 was 70.7 6.- 0 290 7601%.0 149.9 68.0 7. o-NitrodiphenyL..- 290 M 114. 7 143- I. l 0 2) m111.7 1311.5 71.7 9..-. Alpha-nitroanthraquinon 200 400 1 110.1 101. 8l. I 10-- .do 2) 700 128.2 V1.1 68. 11.. p-Nitrobenzoyl chloride. M 400112. l 138.] l. l 12-- ..L o no 700 111.0 in: 3.- Alpha-nitroso-betsnaphthol M 400 112. 2 llifi I A lL- -.do m '1) 121.4 131.0 J 15-- do m750 151.5 197.0 81.5 -dO in m 156. 0 m4. 7 a (WW wood rosin without anytreatment) 100.0 M 5 t 81 (Heated without agen no 400 130. 3 150. 8 680-- do m .mwas 10117 11.1 .-do 20o 700 101. 5 ms; ll E do 700 104.5Ill-1 It,

Most of the products of the above examples were. quite solid, a fewbeing very slightly plastic, for instance, the products of Examples 9,and 12. By "very slightly plastic I mean a consistency such thatsomeimpression may bemade on the material with the flngemail.

At the bottom of the foregoing table the five examples lettered A, B, C,D and E indicate the following:

A=the same WW wood rosin as used in all of the other experiments, so asto indicate the acid value. melting point and consistency of this rosinin its initial untreated state.

B, ,c, Dfand E=blank experiments carried out under the conditionsapplied to the other experiments, except that no treating agent wasemployed during the heating.

In determining melting point, the mercury method was used.

The color of the product may change with the process,although in manycases products of quite light color may be secured, which is ofadvantage Various of the eifects discussed above will be apparent bycomparison of iodine values, acid values, melting points, etc., in theforegoing table. In general, it will be noted that higher tempera turestend to increase the extent of decarboxylation. The effect of' increaseddecarboxyiation shown by reduced acid values usually shows up moreprominently in those examples conducted at reduced pressure. This willbe apparent from comparison of Examples 13 and 14 above. Although theblank experiments also indicate that high temperatures increase theextent'of decarboxylation, careful analysis will show that the increaseof decarboxylation with increase in temperature is greater when themodifying agent is present.

In general, increase in temperature also increases the drop in iodinevalue, the drop in iodine value being greater with increased temperaturewhen the modifying agent is present than in the corresponding blankexperiments. In some cases, for instance, Examples 13 and 14(alpha-nitrosobeta'naphthol) a very substantial drop in iodine valueoccurs, which is most probably due to an aggregation.

With respect to Examples 5 and 6 (employing l-riitropropane) it may bementioned that since this modifying agent has a relatively low boilingpoint, apparently a relatively large proportion thereof was driven oilin the vacuum experiment (400 ms. Hg). This may explain the apparentdiscrepancy in melting points indicated.

Certain variations in procedure may be adopted. For example, certaingases, such as 80:, CO: or nitrogen can be either bubbled through thereaction mass or employed as a blanket on the surface of the batchundergoing treatment. Moreover, the reaction vessel may be such thatgases evolved from the reaction will effectively include air, withouteither applying vacuum or using other gases. n y serve to exclude theair from the reaction but may also be utilized for their supplementalefiect on the material being treated, this subject Expedients of thistype not being more fully considered in my copending application SerialNo 318,650, filed. February 12, 1940, of which the present applicationis a continuationin-part. It is here further noted that certain featuresherein disclosed are also disclosed in my prior U. 8. applicationsSerial No. 386,371, filed April 1, 1941 '(now Patent 2,311,200); andSerial No. 359,425 (now Patent 2,213,944).

Moreover, as disclosed in the above mentioned I copending applications,still other variations in process may be employed for a number ofdifferent purposes, but it is not thought necessaryto discuss thesefully herein, since reference may be made to the copending applicationsfor that purpose. In passing, however, it is noted that additionaltreating agents, of a supplemental character, may also be present duringthe reaction, among which might be mentioned dissolution promotingagents. of the type disclosed in my issued Patent No. 2,293,038. Variouscombinations of modifying agents may also be used for difierentpurposes, including combinations of the modifying agents abovedisclosed, as well as combinations of the modifying agents hereindisclosed with agents disclosed in other of my applications mentionedabove aswell as hereinafter.

It is further to be noted that in general increasing any one or all ofthe variables: namely, temperature, time of treatment and percentage ofmodifying agent, frequently increases the extent of modification, atleast in one respect or another. It will beunderstood that the foregoingis a general rule normally applicable within the ranges of operationabove indicated, although, as to at least some variables, there may belimits beyond which the general rule does not apply.

For instance, excessive increase in temperature may substantially alterthe character of the process as by destructively distilling the product.Increasing the percentage of modifying agent usually increases thedegree of aggregation.

In considering the starting material on which the process may beemployed, it is first-noted that the process brings about changes bothof a colloidal and also of a chemical nature. It is important, however,to bear in mind that the process essentially involves a reaction withthe rosin molecule, that is, with the type of molecules of which thebasic constituents of natural rosin are composed. Therefore, while rosinitself, such as gum or wood'rosins, represents perhaps the mostimportant starting material to which the process is adaptable, it isnoted that the process may be employed on rosin which has beenpretreated in various ways, or on mixed or chemically condensedmaterials incorporating rosin, since the reaction will take placewherever the resin molecule is present provided, of course, that thephysical or chemical state or environment" of the rosin molecule is notsuch as to prevent the reaction from taking place. From the above itwill be seen that rosin esters and thetic resins containing rosin suchas maleic 1 and modified phenolic resins may be treated by the process.

It may also be mentioned that there are other natural resins, such ascopals, which act similarly to rosin by treatment in accordance withthis invention. In fact, the reaction may be carried out on any of thenatural resins containing high molecular resin acids. Therefore,wherever any such other natural resin behaves similarly to rosin, it isherein considered as an equivalent.

Copals are fossil gums which have to be "fused before becoming solublein organic solasaaoci vents and miscible with fatty oil. When copals areused in the present process, they should be employed in the fused state.

The modified product of this invention may if desired, be subject toother treatment, depending upon the use for which it is intended. Thus,for

example, the modified products may be vulcanized with sulphur. Themodified resin products secured in accordance with the foregoing, may bevulcanized as such, or in solutions, such as varnish solutions (in thelatter case with sul-- phur chloride).

Further, they may be converted into emulsions and used for variouspurposes in that form.

In the event sulphur or other sulphur-like vulcanizing agents are used,vulcanization, for certain purposes, is desirably carried out attemperatures between about 120 C. and 200 C. For other purposeswherevulcanization is to be effected at lower. temperatures, for instance, atroom temperature, sulphur chloride, or similarly acting vulcanizingagents, should be used. In

, instances where the vulcanization is carried out this invention areuseful in making rosin modifled maleic and rosin modified phenolicresins.

I claim:

1. A process for making a modified rosin product, which processcomprises dispersing in the rosin from 0.5% to of an'organic compoundselected from the class consisting of nitro-compounds andnitroso-compounds, said compound further being soluble in the rosin andbeing capable of developing an inorganic ozwgen-containing acid ofnitrogen at elevated temperatures when the compound is dispersed inorganic medie, and dissolving said compound in and reacting saidcompound with the resin by heating the mixture to a temperature betweenabout 100 C. and about 350 C., but not above the temperature at whichappreciable destructive distillation occurs under the conditions of thetreatment.

2. A process in accordance with claim 1 in which the temperature isabove about 250 C.

3. A process in accordance with claim 1 in which the reaction is carriedout out of contact with the atmosphere,

4. A process in accordance with claim 1 in which the process is carriedout at atmospheric pressure; V

'6. A process in accordance with claim 1 in heat treatment.

'9. A process in accordance with claim 1 in which the organic compoundis a nitro-compound and is an anthraquinone derivative.

10. The process in accordance with claim 1 in which the organic compoundis a nitro-compound and is a benzene derivative.

' 11. A process in accordance with claim 1 in which the organic compoundis a nitro-compound and is a naphthaline derivative.

12. A process in accordance with claim 1 in which the organic compoundis a nitro-compound and is an aromatic hydroxy compound.

13. A process in accordance with claim 1 in which the organic compoundis a nitro-compound and is alpha-nitroanthraqulnone.

14. A process in accordance with claim 1 in which the organic compoundis a ultra-compound and is a nitrophenol.

15. A process in accordance with claim 1 in Y which the organic compoundis a intro-compound and is alpha-nitroso beta-naphthol.

18. A process for making a modified rosin product, which processcomprises dispersing in the,

rosin from 0.5% to 10% of an aromatic nitrocompound, said compound beingsoluble in the rosin and being capable of developing an inorganicoxygen-containing acid of nitrogen at elevated temperatures when thecompound is dispersed in organic media, and dissolving said compound inand reacting said compound with the rosin by heating the mixture to atemperature between. about 100 C. and about 350 C., but not above thetemperature at which-appreciable destructive distillation occurs underthe conditions of the treatment.

17. Aprocess for making a modified rosin product, which processcomprises dispersing in the rosin from 0.5% to 10% ofan aromaticnitrosocompound, said compound being soluble in the rosin and beingcapable of developing an inorganic oxygen-containing acid of nitrogen ateleof the treatment.

which the heating is continued until the resultant product has decreasedacid value, as compared with the acid value of the same rosin heated to18. A process for making a modified rosin product, which processcomprises dispersing in the rosin from 0.5% to 30% of an organiccompound selectedfrom the class consisting of nitro-compounds andnitroso-compounds, said compound further being soluble in the rosin andbeing capable of developing an inorganic oxygen-containing acid ofnitrogen atelevated temperatures which the organic compound is anaromatic organic compound.

1 ms'zm AUER.

